. >> couric: now to japan. a u.n. expert says radiation continues to leak from those damaged nuclear reactors but progress is being made. all six reactors are now hooked up to power lines-- a step toward getting the cooling systems working once the electricity is turned on. the number of workers at the plant is now up to a thousand. meanwhile, the official death toll from the earthquake and tsunami is approaching 10,000 with nearly 14,000 missing. more than a quarter million survivors have no homes or have been forced to leave them. from japan tonight, here's lucy craft. >> reporter: cardboard houses, now home for thousands living on the floor of a sports arena outside tokyo. all survived the tsunami and quake only to be caught up in a radiation scare. this fifth grader says "we escaped to my school but when they said even that was not safe, we came here." natives of iwaki like to boast about its postcard scenery and mild climate. the now notorious fukushima nuclear plant only 30 miles away has triggered a mass exodus